Fractionation of protein containing mixtures

Abstract

Thus, a primary aspect of the present invention relates to a method for the fractionation of a protein-containing mixture wherein the protein-containing mixture is selected from the group consisting of milk, milk derived products, milk derived raw materials, vegetable derived products, vegetable derived extracts, fruit derived products, fruit derived extracts, fish derived products, and fish derived extracts, said method comprising the steps of: a) optionally adjusting the pH of the mixture; b) applying said mixture to an adsorption column comprising an adsorbent, said adsorbent comprises a particle with at least one high density non-porous core, surrounded by a porous material, the adsorbent having a particle density of at least 1.5 g / ml and a mean particle size of at most 150 μm; c) optionally washing the column; d) eluting at least one protein from the adsorbent.

Description

FIELD OF THE INVENTION The invention relates to an industrial production process and method for the isolation and fractionation of biomolecular substances, particularly proteins in milk and whey products as well as other milk derived raw materials. The selection of adsorbent allows for industrial scale separation of proteins from large volumes of liquids. BACKGROUND OF THE INVENTION Milk is one of the most thoroughly researched foods in history. Countless scientific papers document milk's composition and describe the biological functionalities in this complex bio-resource. Proteins, peptides, enzymes and other biomolecular substances constitute a major and very important fraction in milk and are believed responsible for many of the specific functionalities passed on from a mother to her new-born in addition to basic nutrients. During the past two decades, there has been significant focus on utilisation of bovine whey proteins. Today, several bovine Whey Protein Concentrates (WPC)...

AI Technical Summary

Benefits of technology

One object of the present invention is to provide a process for industrial-scale fractionation of proteins from raw materials using EBA methodology by selection of EBA adsorbents. As stated, this object is achieved at least in part by providing an EBA process utilising a specific adsorbent selected according to its particle diameter and particle density. This allows an EBA process for operating efficiently at linear flow rates above at least 200 cm / hour.

Problems solved by technology

By contrast, traditional packed beds work as depth filters that can clog, resulting in increased back-pressure unless the feed is thoroughly clarified.

If the density is too low, the media will be lost in the column effluent.

Unfortunately, the most interesting materials for many applications, e.g. materials such as natural and synthetic polysaccharides like agar, alginates, carrageenans, agarose, dextran, modified starches, and celluloses; synthetic organic polymers and copolymers typically based on acrylic monomers used for chromatographic purification of proteins in packed bed columns are not of suitable density per se.

Therefore, these materials are not readily applied in EBA.

However, certain types of organic polymers and certain types of silica based materials may be produced to provide carrier particles of suitable density, but such carriers may not at the same time be suitable adsorbents, e.g. for protein purification procedures, where such materials may provide low permeability, non-specific interactions and denature bound proteins.

Further, for such polymers, it may be difficult and expensive to design derivatisation schemes for affinity chromatography media.

However, the properties of these materials are far from optimal.

Thus, the materials are unstable at pH above 7, fragile to shear forces, and provide non-specific interactions.

However, no commercial processes for milk and whey fractionation are based on EBA so far.

Current processes are not capable, in practice, to achieve the level of performance for these and certain other raw materials.

Typically, these precipitation methods are giving very impure products while at the same time being time consuming and laborious.

Furthermore, the addition of the precipitating agent to the raw material makes it difficult to use the supernatant for other purposes and creates a disposal problem.

However, this method is not generally applicable because of the restraints in ionic strength and pH necessary to ensure efficient binding of the antibody together with the varying isoelectric points of different immunoglobulins.

Although being popular it is however recognised that Protein A and Protein G poses several problems to the user among which are: very high cost, variable binding efficiency of different monoclonal antibodies (particularly mouse IgG1), leakage of Protein A / Protein G into the product, and low stability of the matrix in typical cleaning solutions, e.g. 1 M sodium hydroxide.

Each of these drawbacks have its specific consequence in the individual application, ranging from insignificant to very serious and prohibitive consequences.

The disadvantage of this procedure is the necessity to add lyotropic salt to the raw material as this gives a disposal problem and thereby increased cost to the large scale user.

The addition of lyotropic salts to the raw materials would in many instances be prohibitive in large scale applications as the salt would prevent any economically feasible use of the immunoglobulin depleted raw material in combination with the problem of disposing several thousand litres of waste.

Although the matrices described for thiophilic chromatography generally show good performance, they also have a major disadvantage in that it is needed to add lyotropic salts to the raw material to ensure efficient binding of the immunoglobulin, which is a problem for the reasons discussed above.

However, all these affinity matrices still have inadequate affinity constants to ensure an efficient binding of the antibody without added lyotropic salts.

Images